Article of manufacture



ARTICLE OF MANUFACTURE Filed Jan. 20. 1930 INVENTOR George/14 Barrow ATTORNEY Patented Aug. 16, 1932 UNITED STATES PATENT OFFICE GEORGE M. BARROW, O]? DERRY, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELEC- TRIC & MANUFACTURING COMPANY, A CORPORATION 01' PENNSYLVANIA ARTICLE OF MANUFACTURE Application filed January 20, 1930. Serial No. 422,045.

My invention relates to articles of manufacture and particularly to articles including inorganic ceramic or refractory dielectric elements that are homogeneously united to metal elements for use in electrical service.

One object of my invention is to provide an article of the above-indicated character that shall be protected against disintegration, under certain conditions.

Another object of my invention is to provide an article, ordinarily requiring special skill for tinning the same and for soldering it to a cooperating object, that shall be constructed with the tin thereon, to render the tinning unnecessary in the field, preparatory to soldering the article to a metal object.

Another object of my invention is to prevent radio interference ordinarily caused by alternating-current voltage insulators of certain types.

Another object of my invention is to pro-- vide better contactbetween the dielectric material of an insulator and its associated conducting elements.

A further object of my invention is to provide an article of manufacture for the abovementioned purposes that shall be simple and durable in construction, economical to manufacture and effective in its operation.

It has heretofore been suggested to coat dielectric articles with metal by various processes, such as spraying, electrolytic deposition and metallic glazing.

The spraying and electrolytic deposition processes are effective where no considerable mechanical stress is to be imposed upon the coating, as, otherwise, since there is little or no molecular cohesion between the dielectric and metal materials, the metal coatings may be peeled from the dielectric element with comparative ease. This is true whether the dielectric material be of organic or of inorganic material but is particularly true of inorganic materials, such as porcelain.

While metallic glazing of inorganic dielec trio material, such as porcelain, is a comparatively old suggestion, it has only recently, so far as I am aware, been successfully performed in such manner as to provide me tallic-glaze layers of such sensible or practical thickness so that metallic objects of sensible size may be secured thereto in a mechanically strong, fluid-tight and homogenetus way.

Insulators of the pin type have been provided with a metallic-glaze surface, such as a platinum-glaze surface, covering the conductor and tie-wire groove portions as well as the pin recess portions, for the purpose of reducing the corona or leakage effect between a conductor and the dielectric material comprising the insulators and thereby reducing or eliminating radio interference caused by such effect. While the metallicglaze surface coating functions well for a time to accomplish this purpose, nevertheless, due to oxidation and disintegration of the metallic-glaze caused by service conditions, the beneficial effects of employing it is greatly reduced and even lost altogether after a comparatively short time.

By employing my invention, the oxidation and disintegration of the metallic-glaze is prevented and, therefore, the beneficial effects of the metallic-glaze for the prevention of radio interference is maintained indefinitely.

Figure 1 of the accompanying drawing, is a top plan view of an article of manufacture, in the form of an insulator of the pintype, embodying my invention,

Fig. 2 is a side view, partially in elevation and partially in section, of the structure shown in Fig. 1, together with a conductor and a tie wire that are not shown in Fig. 1.

Referring to Figs. 1 and 2, the device comprises, in general, a top shell 2 and a bottom shell 3 that may be of a homogeneous onepiece mass, may be united, as shown, by a body 4: of cement, alloy or other medium or may be spaced farther apart for the interposition of a similar shell or shells that may likewise be homogeneous parts thereof or bonded thereto, as desired.

The top shell or portion 2 comprises a usual top straight groove 6 for the reception of a conductor 7, an annular groove 9 thereunder to receive a tie wire 10 for holding the conductor 7 in position, a main petticoat 12, an under flange 14 and a lower recessed portion 15 of inverted substantially cupshape.

The bottom shell 3 comprises an upper head portion 17 of inverted substantially cupshape fitting the recessed portion 15 of the top shell 2, an outer petticoat 18, an inner petticoat 19 and a pin-receiving recess 20.

a In an ordinary insulator, of the above-described type, the shells 2 and 3 are usually constructed of inorganic dielectric material having an outer surface of a hard brittle nature against which the'conductors 7 and 10 are tied in abutting contact. This relation is conducive to electrostatic discharges between the conducting and dielectric materials which cause radio interference, produce heat which is likely, under certain conditions, to injure the dielectric material and effect disintegration of the, conducting material.

In a known form of insulator, the conductor groove and the tie-wire groove are coated with a metallic glaze which avoids minute air gaps and prevents the discharges between the dielectric and the metal coating normal thereto but does not, under certam conditions, prevent steamer discharges from the conductor to adjacentdielectric surfaces which are not metallized. The latter streamer discharges cause chemical disintegration of the metallic glaze which shortens the effective life of the glaze. Also, there may be a certain amount of physical disintegration caused by friction between the hard conductor and the hard metallic glaze resulting from oscillations of the line conductor.

According to my present invention, as illustrated more clearly in Fig. 2, the insulator is also provided with metallic glaze coatings 22, 23 and 24 in the conductor groove 6, the tie-wire groove 9 and the pin recess 20, respectively, the coatings in the conductor and tie-wire grooves being essential, and the coating in the pinrecess being. more or less optional, depending on the character of the pin and the conditions pertaining to its shape and the manner in which it is secured.

The insulator,'as thus far described, is substantially identical with the known form of insulator mentioned above in which the metallic-glaze coatings are subject to disintegration by chemical reaction from streamer flashes, from friction with the conductors 7 and 10, and from other causes.

The essential improvement of this invention resides in the provision of superposed layers or films 26, 27 and 28xof lead-and-tin solder alloy, or the equivalent, on the metallic films 22, 23 and 24, respectively, the layers 26, 27 and 28 requiring special skill for the positioning thereof and their provisions rendering the article finished for the soldering operation in the field. The layers 26, 27 and 28 also protect the metallic-glaze layers 22, 23 and 24 against disintegration from any of the causes above mentioned. Y

Further advanta of providing a bime' tallic coating on e dielectric member, as set forth, lie in the additional dissipation of heat, protection of the metallic glaze from disintegration by oxidation greater electrical conductivity and the bridging of possible ga s in the metallic-glaze surface.

en the conductor 7 and the tie-wire 10 are bound in position, the softer outer layers of metal yield under pressure so that they conform to, and provide greater contact area with, the conductors. The conductor and the tie wire may be placed in merely abutting relation to the tin coatings or be inte allg united thereto by solderin in the gld.

lso, by permitting the field-so dering operation, the tie wire 10, may be omitted entirely, in accordance with conditions or as desired, and the conductor 7 be soldered directly to the insulator. I While I have shown and described particular forms of my invention, changes may be effected therein without departing from the spirit and scope thereof, as set forth in the appended claims.

I claim as my invention:

1. In combination, in an insulator of the 7 pinype for supporting a transmission-line conductor b a tie wire in merely abuttin contact wit the dielectric material and thereby capable of causin radio interference by discharges from t e conductor and tie wire to the insulator, a silicate-glazed porcelain body having top conductor-receivmg and tie-wlre grooves, and means for reducing said discharges including a fired film of metal glaze containin platlnum on the silicateglaze in the con uctor and tie-wire grooves and confined within a redetermined area local to said grooves, an a coating of lead-and-tin solder fused to the metal glaze thereover.

2. In combination, in an insulator for supportin a transmission-line conductor by detachab e means held in merely abutting con- .tact with the dielectric material and thereby capable of causin radio interference by discharge from sai conductor and means to said material, an inorganic dielectric body having a terminal portion for receiving said conductor and said means, and means for reducing said discharges including a metalglaze film integrally united to said body over the surface of said terminal under said detachable holding means and the conductor and confined within a predetermined area 10- cal to said terminal portion, and a conducting protective coating of different metal coverlng, and fused to, said film.

. .3. An insulator including a dielectric member having a portion thereof in contacting relation with a conductor, and means for reducing electrical discharges between the conductor and the dielectric member, said means comprising a fired metallic-glazefilm intimately united to the surface stratum of the dielectric member, which film covers a surface area of the dielectric member including that of the ortion in contacting relation with the con uctor and extending a limited distance away therefrom, and a coating of solder covering the film in intimate joinder thereto.

In testimony whereof, I have hereunto subscribed my name this 11th day of January,

GEORGE M. BARROW. 

